It has been reported in U.S. Pat. Nos. 6,800,660, 6,762,204, 7,037,940, 7,001,923, and 6,924,312 that certain bis(thio-hydrazide amide) compounds significantly enhance the anti-cancer activity of taxol and taxol analogs. In addition, methods of preparing bis(thio-hydrazide amide) compounds have been reported in U.S. Pat. No. 6,825,235. The entire teachings of these patents are incorporated by reference herein. Moreover, the bis(thio-hydrazide amide), N-malonyl-bis(N′-methyl-N′-thiobenzoylhydrazide), in combination with Taxol has been shown to increase the time to progress of patients suffering from stage 1V metastatic melanoma in relation to patients treated with Taxol alone. However, the synthesis of bis(thio-hydrazide amide) compounds has been complicated by the formation of regioisomers, and the effective administration of N-malonyl-bis(N′-methyl-N′-thiobenzoylhydrazide) has been challenging due to low solubility of the compound. Therefore, it would be advantageous to have new methods of preparing bis(thio-hydrazide amide) compounds.